Vinyl fluoride is a useful monomer for the preparation of fluorocarbon polymers which have excellent weathering and chemical resistance properties.
Vinyl fluoride can be produced from acetylene and hydrogen fluoride using mercury catalysts. It can also be produced by the dehydrofluorination of 1,1-difluoroethane. The dehydrofluorination of 1,1-difluoroethane to vinyl fluoride and hydrogen fluoride is an equilibrium reaction. According to published literature the following equilibrium concentrations of vinyl fluoride (VF), based on the moles of VF divided by the moles of HFC-152a+VF, have been determined; about 13% VF at 227.degree. C., about 40% VF at 327.degree. C. and about 99% VF at 427.degree. C.
U.S. Pat. No. 2,599,631 discloses a process for the manufacture of vinyl fluoride by the dehydrofluorination of HFC-152a. The dehydrofluorination is done in the presence or absence of a catalyst. The dehydrofluorination catalysts disclosed include oxygen, charcoal, and the free metals, salts and oxides of the elements of Groups IA, IB, IIA, IIB, VB and VIII of the periodic table. In an example using the divalent Group II metal compound calcium fluoride as a catalyst (at about 500.degree. C.), the conversion of HFC-152a to vinyl fluoride was 66% (i.e., about 66% of equilibrium). There is an ongoing interest in developing more efficient catalysts for the conversion of HFC-152a to VF.